The invention relates to a movement-adaptive transversal-recursive noise suppression circuit for a television signal, comprising a first combining circuit having a first input coupled to an input of the noise suppression circuit and a second input coupled to an output of a delay circuit, an input of which is coupled to an output of the first combining circuit, the output of the delay circuit further being coupled to a first input of a second combining circuit, a second input of which is coupled to the input of the noise suppression circuit.
Revue de Radio-Diffusion-Television No. 62, April/May 1978, pages 35-42 discloses a noise suppression circuit of the above-described type, the first input of the second combining circuit being coupled via a movement information-dependent transfer circuit to the output of the delay circuit which has a delay of a picture period and the second input of the first combining circuit being coupled to the input of the noise suppression circuit via a complementary movement information-dependent transfer circuit, while the first combining circuit is movement information-dependent so that the noise suppression circuit changes from recursive to transversal accordingly as more movement occurs in a picture to be displayed. A given ratio of movement information-dependent transfer factors of the signal paths via the first and the second combining circuits is mentioned as the most advantageous ratio.
As Applicants have found, such a noise suppression circuit has the advantage, when used in color difference signal paths of color television receivers, that in both the transversal and the recursive state of the noise suppression circuit, a suppression of the cross-talk effect from the luminance signal to the chrominance signal in the color difference signals also occurs.